Pathogenic infections, such as fungal infections, of animals including humans and plants produce significant losses in productive capacity worldwide. A great number of pathogens are responsible of important economical losses in crops and harvested products. For instance, Penicillium and Botrytis species are responsible for important economical losses. The common occurrence of these species in food is a particular problem. Some species produce toxins and may render food inedible or even dangerous. Species of Penicillium can cause severe fruit rot for example on apples (Malus), pears (Pyrus) and lemon (Citrus spp).
Pesticides against pathogens are well known in the art and have been intensively used for many years. Methods for the prophylactic and/or therapeutic treatment of fungal and bacterial infections in animals and plants generally involve the application of anti-fungal and anti-bacterial agrochemical products or the use of more environment-friendly biopesticides based on biocontrol agents. The interest for biological control over chemical control is rapidly growing for some reasons, such as residual reduction, environmental concerns, apparition of pathogen strains resistant to chemical pesticides or limitation of use of chemical pesticides.
As biocontrol agents, micro-organisms that are antagonistic to pathogens are known. Documents which relate to the use of compositions comprising yeast's or other micro-organisms against plant pathogens have been published, amongst which EP 1 238 587 which discloses in its examples composition comprising an antagonistic microorganism with high concentration of CaCl2 2% (20 g/l). WO 99/62340, WO 99/62341, U.S. Pat. No. 5,525,132, U.S. Pat. No. 5,741,699, U.S. Pat. No. 6,060,429, WO 00/44230, U.S. Pat. No. 5,288,488 and U.S. Pat. No. 5,780,023 may be cited as other examples.
Various micro-organisms amongst bacteria, fungi and yeast's have successfully been used against plant diseases caused by pathogens. Commercial biocontrol products such as Aspire™ (Candida oleophila Montrocher, 1-182) and Biosave™ (Pseudomonas syringae van Hall, Esc-11) was and are already available respectively from Ecogen Inc. (Longhorn, Pa.) and Ecoscience Corp. (Worcester, Mass.) and are used among others on postharvest apples against wound diseases.
However these biopesticides were often found not efficient enough. These first generation biocontrol products, relying on the use of single antagonists, have been criticized for not providing a stable and reliable protective activity when used under commercial conditions. To improve their natural ability to control fungi and particularly Penicillium expansum infections, reduce volume to handle, and costs, new stimulating agents have been searched.
Indeed, more efficient compositions enable to use lesser quantities of antagonistic micro-organisms per treatment, without lowering the efficiency of the composition against pathogens and without restricting the duration of the efficiency of the composition against pathogens, and, so, to reach the economical threshold of profitability.
In view of the foregoing, it is a main object of the present invention to provide novel compositions which are suitable for use against diseases caused to plants, product thereof and animals by pathogens, such as diseases induced by moulds. Another object of the present invention is to provide compositions that are at least as efficient as the ones of the state of the art. A further object of the invention is to provide compositions which comprise lower concentrations of antagonistic micro-organisms while having a similar or better efficiency against the pathogens.